A Letter of Credit is a document that guarantees payment from the importer's bank to the exporter's bank. In this way it is similar to a home loan where the bank guarantees payment from the buyer to the seller, although the importer usually already has the funds to purchase the goods, but needs the bank's guarantee to reassure the exporter of payment. A typical Letter of Credit will state that when a specific condition has been met, (usually the exporter providing proof of shipment) the importer's bank will release the payment to the exporter's bank.

LC is Letter of Credit that is a letter that banks will provide to seller side of a transaction to verify that the buyer is able to pay that amount of money , in case if the buyer don't pay the seller the bank has to pay the seller.

TT is Telegraphic Transfer that is also called wire /swift transfer which is cheap and fastest legal way of remitting money over seas through any bank with forex facility by the way you have to be careful before you buy any such things from companies before you should know them well